I'd say your first nap is probably too early, which is why it's short. Then with your second A time being over 4 hours, he has to be OT before he goes down for that nap, which probably messes with that.
If you want to continue taking a walk with him each day (who wouldn't, it helps us all to get out!), I'd either do it earlier so he doesn't fall asleep or do it closer to 10:30/11 so he'll take a (hopefully) longer nap after a more age appropriate A time (which would be about 3-4 hours for a baby his age). Or, if he does a shorter nap, I'd put him down earlier for that second nap.
With regard to teeth, have you tried medicating at all? Do you notice any difference? The cry you describe sounds like it could be discomfort to me.